1. Field of the Invention
The invention relates to a device for attachment to a cross-country ski to arrest backward sliding of the ski on an inclined surface. More specifically, the invention relates to such a device which is self-cleaning.
2. Description of Prior Art
It is known in the art to provide means for arresting backward sliding of cross-country skis. One example of such a device is illustrated in U.S. Pat. 1,401,940, Beckman, Dec. 27, 1921. The Beckman patent teaches a pivoting arm 1 with means to limit the upward and downward swinging movements of the arm 1. The end of the arm has a sharp point which is dangerous as persons waxing the ski could quite easily cut themselves. In addition, snow can gather in the device and freeze to ice causing a cessation of the operation of the Beckman device.
A further arrangement is illustrated in U.S. Pat. No. 1,665,537, Dumais, April 10, 1928. In the Dumais patent, tines 23 are mounted to pivot freely on the ski. The tines extend on either side of the ski. The tines of the Dumais arrangement have the same disadvantages as the arm of the Beckman arrangement in that they are dangerous and are subject to freezing over.
U.S. Pat. No. 2,077,660, Barieau, April 20, 1937 and U.S. Pat. No. 2,107,363, Binder, Feb. 8, 1938, both teach cleats for climbing hills. The cleats do not operate automatically but have to be manually moved from an operating to a nonoperating position and vice-versa.
U.S. Pat. No. 2,122,718, Hikel, July 5, 1938 teaches an extension 24 which overhangs one edge of the ski and is spring-biassed downwardly. When a skier moves in the forward direction, the extension 24 will be dragged along the ground by overcoming the bias of the spring. When the ski attempts to exhibit backward motion, the extension 24 will extend downwardly and stick into the ground to prevent this backward motion. The Hikel device is also subject to freezing up.
U.S. Pat. No. 2,232,443, Farmer, Feb. 18, 1941 teaches freely pivoted tongues 33 extending on both sides of the ski with means for limiting the movement of the tongues. This arrangement is also subject to freezing up.
U.S. Pat. No. 2,199,721, Coffin, May 7, 1940 teaches a freely pivoted dog 1 which extends on one side of the ski. The dog is fixed to the ski with a clamp to easily mount or remove the dog from the ski. This arrangement is also subject to freezing.
U.S. Pat. No. 2,316,252, Karlsson, April 13, 1943 teaches spring-biassed blades 13 extending on either side of the ski. The blades are biassed downwardly so that the arrangement works similar to the manner in which the Hikel device, referred to above, works. This arrangement is also subject to freezing up.
U.S. Pat. No. 2,375,943, Rape, May 15, 1945 teaches the use of climbing blades 1 which have to be manually removed and mounted.
In all of the above arrangements, as the means which stick into the ground are basically in a single plane, they will arrest motion in one direction only, namely, in the longitudinal direction of the ski. They will not arrest motion in the lateral direction of the ski.